2.3. Replacement of spark plugs

Spark plugs replace at planned maintenance service.

If off-schedule replacement of spark plugs is necessary, apply only the spark plugs recommended for the given engine.

It will allow to avoid failures of the engine, decrease in its capacity, deterioration приемистости, increases of the maintenance of harmful substances in the fulfilled gases and creations of hindrances for radio reception. Especially important characteristics of candles: quantity of electrodes, калильное number, on occasion ability not to create hindrances to radio reception.

Normal work of spark plugs — one of the major conditions of effective work of the engine. On the engine establish only the spark plugs recommended by manufacturer. At the serviceable engine cleaning of spark plugs carry out seldom.

Replace and check up spark plugs in a following order:

Fig. 2.5. Removal of a tip of a high-voltage wire from a spark plug: it is necessary to pull for a tip (1), instead of for a high-voltage wire (2)

- Pull for a tip 1 (fig. 2.5) a high-voltage wire and remove it from a spark plug. Do not pull for a high-voltage wire;

- Clear candles a brush, a vacuum cleaner or a stream of compressed air to prevent dirt hit in cylinders of the engine after вывинчивания spark plugs;

- Turn out candles a candle key.

On appearance of spark plugs продиагностируйте an engine condition. Pure, white without a touch the insulator of spark plugs testifies about too poor топливовоздушной mixes. It also specifies that a candle too hot (warmly from the central electrode it is taken away slowly). Adjust structure топливовоздушной mixes or replace a candle.

Adjournment of a dry soot specifies in too rich mix. If the touch the black, oily engine is worn out, it should be checked up and repaired. If the insulator is covered by light brown touch, mix structure optimum, and the engine in a good condition.

Fig. 2.6. A place of measurement of an interelectrode backlash () spark plugs

Too big and too small interelectrode backlash at which the size of a spark changes, reduces an engine overall performance (fig. 2.6). The backlash always should correspond to technical requirements.

The backlash is checked by a wire template or щупом. To modify a backlash it is possible подгибанием a lateral electrode the special tool. The central electrode cannot be bent. It can lead to breakage of an insulator and a candle exit out of operation.

Before spark plug installation in the engine check up, that the carving was pure and intact.

Clean high-voltage wires and check up them on absence обгорания, a break or other damages. Check up the ends of fastening of wires with the distributor of ignition and candles. Replace wires if it is necessary.